1. Technical Field
The present invention relates to a radio signal receiver that receives radio frequency signals, an electronic device, and a radio signal receiving method.
2. Related Art
An example of a radio signal receiver that receives satellite signals and other RF signals, determines if the radio signal receiver is outdoors, and receives signals if the receiver is determined to be outdoors is described, for example, in JP-A-2013-50343.
The wrist watch disclosed in JP-A-2013-50343 has a solar panel, and determines if the wristwatch is outdoors or not based on the power output of the solar panel. The wristwatch receives satellite signals if the wristwatch is determined to be outdoors. If the wristwatch is determined to be indoors and not outdoors, and continues to be indoors for a predetermined time or longer, the wristwatch receives satellite signals at a previously set scheduled reception time.
Wasteful consumption of power can therefore be suppressed when the wristwatch is indoors where the possibility of failing to receive satellite signals is high because the satellite signals are not received unless the wristwatch remains indoors for at least a specific time. On the other hand, when the wristwatch is outdoors but cannot be determined to be outdoors because the wristwatch is covered by a sleeve or because the amount of light reaching the wristwatch is weak due to seasonal or weather-related factors, satellite signals are received at a preset scheduled reception time when this state continues for a specific time or longer.
However, when the user wearing the wristwatch disclosed in JP-A-2013-50343 is in a location with good light exposure for only a short time and then moves indoors, the wristwatch may be determined to be outdoors and reception may begin, but then cannot correctly receive the satellite signals because moving indoors makes reception impossible. Power is therefore wasted by the reception attempt.
Furthermore, because an outdoors location is not determined unless the wristwatch is exposed to outdoor light, the possibility that the wristwatch will be determined to be outdoors during a specific time will be low if the wristwatch is only used at night. This specific time is 24 hours, and reception at the scheduled reception time only occurs once a day. As a result, when the wristwatch is only used at night, the possibility that the next reception will not occur at the next scheduled reception time but at the scheduled reception time next after the specific time (24 hours) has past is high. As a result, when the wristwatch is used primarily at night, the average reception interval becomes longer than the interval between the scheduled reception times.